title: A comparative study of the analysis of human urine headspace using gas chromatography-mass spectrometry.
abstract: First-void urine samples were obtained from 24 elderly, asymptomatic men (median age 62.9 years). The headspace above pH adjusted urine samples were extracted using a carboxen/polydimethylsiloxane solid phase micro-extraction fibre and the volatile organic compounds analysed by gas chromatography/mass spectrometry. A total of 147 compounds were identified in the headspace of urine. The acidified samples recorded a total of 92 compounds, 27 of which were ubiquitous, basified samples 70 compounds, with 12 ubiquitous and unmodified pH samples 49, with 6 ubiquitous. Five compounds were ubiquitous irrespective of pH: acetone, methylene chloride, 4-heptanone, 2-pentanone and 2-butanone. A comparative analysis of unfrozen and frozen-thawed urine (stored at room temperature for 0, 1 and 8 h) showed that samples retained the same number of compounds although variations in the peak areas for some compounds were observed.
authors.affiliation: Centre for Research in Analytical, Materials, and Sensor Sciences, University of the West of England, Bristol, BS16 1QY, UK.
authors.forename: S
authors.initials: S
authors.lastname: Smith
authors.forename: H
authors.initials: H
authors.lastname: Burden
authors.forename: R
authors.initials: R
authors.lastname: Persad
authors.forename: K
authors.initials: K
authors.lastname: Whittington
authors.forename: B
authors.initials: B
authors.lastname: de Lacy Costello
authors.forename: N M
authors.initials: NM
authors.lastname: Ratcliffe
authors.forename: C S
authors.initials: CS
authors.lastname: Probert